Branches of biotechnology

1 plant tissue culture – It is a technique of growing plants cells, tissues or organs in an artificially prepared nutrient medium under aspectic condition. In this technique, a growing tissue is excised from plant and kept in a callus inducing artificial medium to produce calli. Calli are the undifferentiated and unorganized cells. These calli can regenerate green plants after putting them into
a regeneration medium.
Tissue ? callus ? plant regeneration
Environmental conditions like light, temperature, hormones( auxins and cytokinins), and nutrients can have important role in achieving plant tissue in vitro.
This technique has become extemely significant in agriculture.
Following are the benefits of plants tissue culture (PTC):
• Rapid clonal propagation of economically important plants in large number,
• Maintaining pathogen free plants,
• Possibility of wide hybridization,
• Increase in plant productivity,
• Improvement of variation among plants,
2 Protoplast
Protoplast is a cell without cell wall. Protoplast can be obtained, cultured and fused. A complete plant can be obtained from a single protoplast culture. It is useful in-
? Obtaining germ free plants,
? Introduction of foreign genes, and
? Fusion of two incompatible plants.
3 Gene transfer
Gene is a part of a DNA segment with a particular character. ( DNA segment that expresses a character is called gene). Many useful genes like Nif gene, kanamycin resistant gene, luciferease gene, etc. have been known and isolated. In this technique, a foreign gene of interest can be inserted into other plants by the following methods:
• Direct gene transfer – It is the process of transfer of a gene interest directly into plants by conventional breeding, protoplast fusion, etc.
• Agrobaterium mediated DNA transfer technology – it is the process of transfer of gene from a plant to other plants through Agrobacterium tumefaciens.

4 Hybridoma technology – this technique is used to fuse a normal antibody-producing lymphocytes (B cells or plasma cells) with myeloma cell (a kind of tumor cells) giving a hybridoma. Hybridoma has the potential to grow indefinitely in culture and hence can be source of unending supply of an antibody of choice. Since the antibody produced by a hybridoma is biochemically pure, it is called monoclonal antibody. Monoclonal antibodies are used for detection of animals and plants diseases.
Using this technique, various types of antibodies, vaccines, hormones, enzymes, kits for early diagnosis of diseases, etc. have been developed.
Genetic engineering – it is also known as recombinant DNA technology. In this technique, a piece of foreign DNA is inserted into DNA of a vector (foreign DNA + vector DNA) is multiplied and/or expressed by introducing the vector into a bactrium. This approach is used for DNA sequencing and commercial production of proteins.